Hyperthyroidism and concurrent thyroid cancer.

A total of 14 patients had hyperthyroidism coexisting with thyroid malignancy. Twelve patients had papillary cancer, 1 follicular cancer and 1 anaplastic cancer. Patients with Graves' disease had a low rate of associated malignancy 1.5% (10/674) and toxic nodular goiter had an incidence of 3.1% (4/27). Subtotal thyroidectomy was performed in 11 patients, total thyroidectomy in 2 and biopsy only in 1. Two of the subtotal thyroidectomy groups had to be operated on again due to their size being over 1 cm. In the follow-up period, only one patient died of anaplastic cancer in the second month. One patient who had multiple foci of the papillary cancer had local recurrence and lymph node metastasis 27 months later, and needed another radical neck dissection. All the other 12 patients were doing well without cancer recurrence. In conclusion, hyperthyroidism may have a malignancy of 1.75% (14/801). Subtotal thyroidectomy is adequate for occult cancer. Those patients with multiple foci, cancer size over 1 cm and capsule invasion should have a second operation with total thyroidectomy.